The present invention relates to an improved switch assembly.
A known type of rotary switch comprises a stator plate formed with an electrically conductive printed pattern on one side thereof. Terminals are fastened to the stator plate and are connected to the respective portions of the pattern through printed connections which extend from the terminals along the opposite side of the stator plate and through the stator plate to the pattern. A rotor is rotatably supported by the stator plate and carries contacts which bridge the various portions of the printed pattern on the stator plate upon rotation thereof to provide the required switching functions.
This prior art switch has a number of inherent drawbacks which are overcome by the present invention. Due to the basic configuration of the prior art switch, it is difficult to hermetically seal the same for protection against the ingress of dirt and other contaminants. Since the electrically conductive pattern is provided on one side of the stator plate and the printed connections are provided on the opposite side thereof, the number of switching functions is unnecessarily limited. The connection of the terminals to the pattern requires a relatively large number of process steps and the switch is therefore unnecessarily high in cost. Also, the entire stator plate must be redesigned to change the switching functions which limits the interchangeability of parts for physically similar but electrically different switches.
In another type of rotary switch, shown in U.S. Pat. No. 3,736,390 to Lockard and U.S. Pat. No. 3,366,751 to Capellari, a plate is rotatably mounted within a housing. The rotatable plate carries a printed circuit which makes contact with a set of brushes (contacts) which are fixed on the housing. In the Lockhard '390 patent a "flat circular printed circuit board member having a coded circuit etched on one face thereof" may be rotated within the housing and its coded circuit makes contact with brush members 24. In the Capellari '751 patent a rotatable disc may have one printed circuit on one of its sides or two printed circuits on opposite sides of the disc. The disc is rotated so that the printed circuit makes selected contact with stationary contacts carried by flat springs.